(a) `Cr^(3+), [Ar]^(18) 3d^(3)`, (b) `Cu^(+), [Ar]^(18) 3d^(10)`,
(c) `Co^(2+): [Ar]^(18) 3d^(7)`, (d) `Mn^(2+): [Ar]^(18)3d^(5)`
(e) `Pm^(3+), [Xe]^(54) 4f^(5) 5d^(5)`, (f) `Ce^(4+) : [Xe]^(54)`
(g) `Lu^(2+): [Xe]^(54) 4f^(14) 5d^(1)`, (h) `Th^(4+): [Rn]^(86)`.